1. Field of Invention
The invention is directed to ball launching assemblies for releasing balls into wellbores to facilitate completion operations in oil and gas wells and, in particular to surface-located ball launching assemblies capable of launching multiple balls in sequence.
2. Description of Art
Use of balls and ball seats in completion operations are generally known in the art. For example, typical ball seats are tubular members having a bore or passageway that is restricted by a seat. A ball or drop plug is disposed on the seat, preventing or restricting fluid from flowing through the bore of the ball seat and, thus, isolating the tubing or conduit section in which the ball seat is disposed. As the fluid pressure above the ball or drop plug builds up, the conduit can be pressurized for tubing testing or actuating a tool connected to the ball seat such as setting a packer. Ball seats are also used in cased hole completions, liner hangers, flow diverters, frac systems, and flow control equipment and systems.
Although the terms “ball seat” and “ball” are used herein, it is to be understood that a drop plug or other shaped plugging device or element may be used with any ball seats capable of receiving a ball to perform the required completion operation. For simplicity it is to be understood that the term “ball” includes and encompasses all shapes and sizes of plugs, balls, or drop plugs unless the specific shape or design of the “ball” is expressly discussed.
In certain completion operations, it is desired to drop or launch multiple balls into the wellbore so that more than one completion operation can be performed. For example, a first ball may be dropped or launched into the wellbore to set a packer. Thereafter, second, third, fourth, etc. balls may be dropped or launched into the wellbore to set an additional packer, set a bridge plug, set an anchor, run fracturing operations, or any other well completion operation. Multiple ball launch assemblies, thus, are designed to launch multiple balls into wellbores.